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// Copyright 2018 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Implementation for FreeBSD and NetBSD
use crate::{util_libc::sys_fill_exact, Error};
use core::ptr;
fn kern_arnd(buf: &mut [u8]) -> libc::ssize_t {
static MIB: [libc::c_int; 2] = [libc::CTL_KERN, libc::KERN_ARND];
let mut len = buf.len();
let ret = unsafe {
libc::sysctl(
MIB.as_ptr(),
MIB.len() as libc::c_uint,
buf.as_mut_ptr() as *mut _,
&mut len,
ptr::null(),
0,
)
};
if ret == -1 {
-1
} else {
len as libc::ssize_t
}
}
pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
#[cfg(target_os = "freebsd")]
{
use crate::util_libc::Weak;
static GETRANDOM: Weak = unsafe { Weak::new("getrandom\0") };
type GetRandomFn =
unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::ssize_t;
if let Some(fptr) = GETRANDOM.ptr() {
let func: GetRandomFn = unsafe { core::mem::transmute(fptr) };
return sys_fill_exact(dest, |buf| unsafe { func(buf.as_mut_ptr(), buf.len(), 0) });
}
}
// Both FreeBSD and NetBSD will only return up to 256 bytes at a time, and
// older NetBSD kernels will fail on longer buffers.
for chunk in dest.chunks_mut(256) {
sys_fill_exact(chunk, kern_arnd)?
}
Ok(())
}
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